We have developed a state-of-the-art image slicer Integral Field Unit (IFU) for the McMath-Pierce Solar Telescope (McMP) located at Kitt Peak National Solar Observatory. The IFU will be used for high-resolution 3-dimensional spectroscopy and polarimetry over a small field of view that is well corrected by adaptive optics. It consists of 19 effective slices that correspond to a field of view of 6.27``x 7’’. The IFU delivers a 152’’ long slit to an existing spectrograph producing diffraction-limited 3-dimensional spectroscopy. The 3-D instrument is being used for highspatial and high-temporal resolution imaging of the Sun, which is crucial for the magnetic field and spectroscopic studies of 2-dimensional solar fine structures. We discuss the instrument construction, laboratory test and on-site trial observations with the McMP.